Tack giving a white mouse to Yum Yum before confronting Zig Zag and the war machine.
For that matter, Tack feeding a group of mice while imprisoned.
Specifically, he tries to feed the white mouse a few scraps of bread, but a bunch of black mice eat it all, so he give the white mouse the whole loaf of bread.
Tack and Princess Yum-Yum make hearts for each other. To be specific, Tack shows off some of his cobbler skills by making a heart shape out of Yum-Yum's shoe strings. She in turn does the same by, albeit subconsciously, with her flowers. The two blush and it's adorable.
Princess Yum-Yum saving Tack from Zig Zag's unjust wrath by deliberating breaking one of her shoes.